Antireflection hard coating film and preparation method thereof

ABSTRACT

Provided is a hard coating film in which a hard coating layer having a water contact angle of 90° or less, a conductive layer, and a low refractive index layer are laminated on a substrate, the film having excellent hardness, anti-curling property, antireflection performance, antifouling performance, and antistatic performance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No.10-2018-0098463 filed Aug. 23, 2018 and Korean Patent Application No.10-2019-0100237 filed Aug. 16, 2019, the disclosures of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The following disclosure relates to an antireflection hard coating filmand a preparation method thereof.

BACKGROUND

Recently, thin displays using a flat panel display such as an organiclight emitting diode display or a liquid crystal display are drawingattention. Particularly, these thin displays are implemented in the formof a touch screen panel and are widely used in various smart devicescharacterized by portability including various wearable devices as wellas smart phones and tablet PCs.

These portable touch screen panel-based displays are provided with awindow cover for display protection on a display panel for protectingthe display panel from scratches or external impact, and in most cases,tempered glass for a display is used as a window cover. A tempered glassfor a display is thinner than general glass, but is characterized bybeing manufactured to have high strength together with resistance toscratches.

However, the tempered glass has a disadvantage of being not suitable forweight reduction of portable devices due to its heavy weight, isvulnerable to external shock so that it is difficult to implement anunbreakable property, and does not bend above a certain level so thatthe tempered glass is unsuitable as a flexible display material having abendable or foldable function.

Recently, various studies on an optical plastic cover securingflexibility and impact resistance simultaneously with having strength orscratch resistance corresponding to tempered glass have been conducted.In general, examples of optical transparent plastic cover materialshaving flexibility as compared with tempered glass may includepolyethylene terephthalate (PET), polyether sulfone (PES), polyethylenenaphthalate (PEN), polyacrylate (PAR), polycarbonate (PC), polyimide(PI), polyaramide (PA), polyamideimide (PAI), and the like.

However, these polymer plastic substrates exhibit insufficient physicalproperties in terms of hardness and scratch resistance and also does nothave sufficient impact resistance, as compared with tempered glass usedas a window cover for display protection. Thus, various attempts forcomplementing the required physical properties by coating a compositeresin composition on these plastic substrates, have been made. As anexample, a plastic substrate disclosed in Korean Patent Laid-OpenPublication No. 10-2013-0074167 is included.

In the case of a general hard coating, a composition including a resincontaining a photocurable functional group such as (meth)acrylate orepoxy, a curing agent or a curing catalyst, and other additives is used,but it is difficult to implement high hardness corresponding to thetempered glass, a curling phenomenon occurs a lot due to shrinkage atthe time of curing, and also flexibility is insufficient, and thus, thegeneral hard coating has a disadvantage of being not appropriate as aprotective window substrate for being applied to a flexible display.

RELATED ART DOCUMENTS

Korean Patent Laid-Open Publication No. 10-2013-0074167

SUMMARY

An embodiment of the present invention is directed to providing anantireflection hard coating film having improved mechanical properties,hardness, anti-curling property, antistatic performance, antireflectionperformance, and the like.

Another embodiment of the present invention is directed to providing apreparation method of an antireflection hard coating film havingimproved mechanical properties, hardness, anti-curling property,antistatic performance, antireflection performance, and the like.

In one general aspect, an antireflection hard coating film includes: asubstrate; a hard coating layer having a water contact angle of 90° orless, disposed on the substrate; a conductive layer disposed on the hardcoating layer; and a low refractive index layer disposed on theconductive layer.

According to exemplary embodiments, the hard coating layer may includean epoxy siloxane resin, a thermal initiator including a compoundrepresented by the following Chemical Formula 2, and a photoinitiator:

wherein R³ is hydrogen, an alkoxycarbonyl group having 1 to 4 carbonatoms, an alkylcarbonyl group having 1 to 4 carbon atoms, or anarylcarbonyl group having 6 to 14 carbon atoms, R⁴ is independently ofeach other hydrogen, halogen, or an alkyl group having 1 to 4 carbonatoms, n is 1 to 4, R⁵ is an alkyl group having 1 to 4 carbon atoms oran aralkyl group having 7 to 15 carbon atoms which may be substituted byan alkyl group having 1 to 4 carbon atoms, R⁶ is an alkyl group having 1to 4 carbon atoms, and X is SbF₆, PF₆, AsF₆, BF₄, CF₃SO₃, N(CF₃SO₂)₂, orN(C₆F₅)₄.

In exemplary embodiments, the hard coating layer may be a cured layer ofa composition for forming a hard coating layer including the epoxysiloxane resin, the thermal initiator including a compound representedby Chemical Formula 2, and the photoinitiator.

In some exemplary embodiments, the cured layer may be formed byphotocuring and then thermally curing the composition for forming a hardcoating layer.

In exemplary embodiments, the composition for forming a hard coatinglayer may further include a crosslinking agent including a compoundrepresented by the following Chemical Formula 1:

wherein R¹ and R² are independently of each other a linear or branchedalkyl group having 1 to 5 carbon atoms, and X is a direct bond; acarbonyl group; a carbonate group; an ether group; a thioether group; anester group; an amide group; a linear or branched alkylene group,alkylidene group, or alkoxylene group having 1 to 18 carbon atoms; acycloalkylene group or cycloalkylidene group having 1 to 6 carbon atoms;or a connecting group thereof.

In exemplary embodiments, the conductive layer may include a conductivemetal oxide or a conductive metal nitride.

In exemplary embodiments, the conductive metal oxide or the conductivemetal nitride may include any one or more selected from the groupconsisting of an aluminum (Al) oxide doped with any one or more selectedfrom the group consisting of phosphorus (P), indium (In), and antimony(Sb); a titanium (Ti) oxide doped with any one or more selected from thegroup consisting of phosphorus, indium, and antimony; and an antimonyoxide doped with any one or more selected from the group consisting ofphosphorus and indium.

In exemplary embodiments, the low refractive index layer may include aninorganic oxide.

In exemplary embodiments, the inorganic oxide may include silicondioxide (SiO₂).

In exemplary embodiments, the antireflection hard coating film may havea surface resistance of 10⁷Ω/□ to 10¹³Ω/□.

In exemplary embodiments, the conductive layer may have a refractiveindex of 1.6 to 2.6, and the low refractive index layer may have arefractive index of 1.35 to 1.45.

In exemplary embodiments, the hard coating layer may have a refractiveindex of 1.48 to 1.55.

In exemplary embodiments, when the conductive layer and the lowrefractive index layer are defined as an antireflection laminate, theantireflection laminate may be laminated two to six times repeatedly.

In exemplary embodiments, the antireflection hard coating film mayfurther include an antifouling layer including a metal fluoride,disposed on the low refractive index layer.

In exemplary embodiments, the metal fluoride may include magnesium (Mg)or barium (Ba).

In another general aspect, a preparation method of the antireflectionhard coating film includes: applying a composition for forming a hardcoating layer including an epoxy siloxane resin, a thermal initiatorincluding a compound represented by the following Chemical Formula 2,and a photoinitiator on a substrate; curing the composition for forminga hard coating layer to form a hard coating layer; forming a conductivelayer on the hard coating layer; and forming a low refractive indexlayer on the conductive layer:

wherein R³ is hydrogen, an alkoxycarbonyl group having 1 to 4 carbonatoms, an alkylcarbonyl group having 1 to 4 carbon atoms, or anarylcarbonyl group having 6 to 14 carbon atoms, R⁴ is independently ofeach other hydrogen, halogen, or an alkyl group having 1 to 4 carbonatoms, n is 1 to 4, R⁵ is an alkyl group having 1 to 4 carbon atoms oran aralkyl group having 7 to 15 carbon atoms which may be substituted byan alkyl group having 1 to 4 carbon atoms, R⁶ is an alkyl group having 1to 4 carbon atoms, and X is SbF₆, PF₆, AsF₆, BF₄, CF₃SO₃, N(CF₃SO₂)₂, orN(C₆F₅)₄.

In exemplary embodiments, the curing may include phorocuring and thermalcuring which are sequentially performed.

In exemplary embodiments, the formation of the conductive layer may beperformed by sputtering a conductive metal oxide or a conductive metalnitride or sputtering a metal element while supplying oxygen.

In exemplary embodiments, the conductive metal oxide or the conductivemetal nitride may include any one or more selected from the groupconsisting of an aluminum (Al) oxide doped with any one or more selectedfrom the group consisting of phosphorus (P), indium (In), and antimony(Sb); a titanium (Ti) oxide doped with any one or more selected from thegroup consisting of phosphorus, indium, and antimony; and an antimonyoxide doped with any one or more selected from the group consisting ofphosphorus and indium.

In exemplary embodiments, the formation of the low refractive indexlayer may be performed by sputtering an inorganic oxide.

In exemplary embodiments, the inorganic oxide may include silicondioxide (SiO₂).

In exemplary embodiments, the preparation method of the antireflectionhard coating film may further include forming an antifouling layer onthe low refractive index layer.

In exemplary embodiments, the formation of the antifouling layer may beperformed by sputtering a metal fluoride.

In exemplary embodiments, the metal fluoride may include magnesium (Mg)or barium (Ba).

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2, and 3 are schematic drawings illustrating an antireflectionhard coating film according to the exemplary embodiments of the presentinvention.

FIGS. 4 and 5 are schematic flow charts representing a preparationmethod of an antireflection hard coating film according to the exemplaryembodiments of the present invention.

DETAILED DESCRIPTION OF MAIN ELEMENTS

10: Antireflection hard coating film

100: Substrate

110: Hard coating layer

120: Conductive layer

125: Antireflection laminate

130: Low refractive index layer

140: Antifouling layer

DETAILED DESCRIPTION OF EMBODIMENTS

The advantages, features and aspects of the present invention willbecome apparent from the following description of the embodiments withreference to the accompanying drawings, which is set forth hereinafter.The present invention may, however, be embodied in different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the presentinvention to those skilled in the art. The terminology used herein isfor the purpose of describing particular embodiments only and is notintended to be limiting of example embodiments. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof.

The exemplary embodiments of the present invention provide anantireflection hard coating film in which a hard coating layer having awater contact angle of 90° or less, a conductive layer, and a lowrefractive index layer are laminated on a substrate, the film havingsuppressed curling and excellent hardness, antireflection performance,and antistatic performance. In addition, a preparation method of theantireflection hard coating film is provided.

Hereinafter, the exemplary embodiments of the present invention will bedescribed in detail. However, these are only illustrative and thepresent invention is not limited to the specific embodiments which areillustratively described by the present invention.

The terms “curl” and “curling” used herein mean bending deformation of afilm, and “curl amount” means a vertical height from the lowest point ofthe film to a point where the film is bent to be raised when a curledfilm is placed on a flat surface.

The term, “anti-curling property” used herein may refer to acharacteristic of less exhibiting the “curl amount”.

FIG. 1 is schematic drawings illustrating an antireflection hard coatingfilm according to the exemplary embodiments of the present invention.

Referring to FIG. 1 , the antireflection hard coating film 10 mayinclude a substrate 100, a hard coating layer 110, a conductive layer120, and a low refractive index layer 130.

The substrate 100, the hard coating layer 110, the conductive layer 120,and the low refractive index layer 30 may be laminated in this orderwith each layer being in direct contact with each other. In addition,another layer may be interposed between each layer.

It is preferred that the substrate 100 has excellent transparency,mechanical strength, thermal stability, moisture shielding property,isotropy, and the like. The substrate 100 may be manufactured from, forexample, polyester-based resins such as polyethylene terephthalate,polyethylene isophthalate, and polybutylene terephthalate;cellulose-based resins such as diacetyl cellulose and triacetylcellulose; polycarbonate-based resins; acrylic resins such as polymethyl(meth)acrylate and polyethyl (meth)acrylate; styrene-based resins suchas a polystyrene acrylonitrile-styrene copolymer; polyolefin-based resinhaving a polyethylene, polypropylene, cyclo-based or norbornenestructure, polyolefin-based resins such as an ethylenepropylenecopolymer; polyimide-based resins; polyaramide-based resins;polyamideimide-based resins; polyethersulfone-based resins;sulfone-based resins, and the like. These resins may be used alone or incombination of two or more.

The thickness of the substrate 100 is not particularly limited, and forexample, may be 10 to 250 μm.

The hard coating layer 110 may be disposed on the substrate 100.

In some exemplary embodiments, the hard coating layer 110 may have awater contact angle of 90° or less. When the hard coating layer 110 hasa water contact angle of 90° or less, the surface tension of the hardcoating layer 110 is high, so that interlayer bonding force between thehard coating layer 110 and the conductive layer 120 may be improved. Inaddition, the hard coating layer 110 and the conductive layer 120 maymutually prevent deformation, thereby suppressing a curling phenomenonof the entire antireflection hard coating film and improving durability.More preferably, the hard coating layer 110 may have a water contactangle of 80° or less or 50° or less, and 40° or more. In this case, theeffect described above may be more increased.

The water contact angle of the hard coating layer 110 may be adjusted byadding a leveling agent to the composition for forming a hard coatinglayer described later, or performing physical treatment such as coronaand plasma discharge. However, a method of adding a leveling agent tothe composition for forming a hard coating layer may be more easilyperformed in the process.

In exemplary embodiments, the hard coating layer 110 may include anepoxy siloxane resin, a thermal initiator including a compoundrepresented by the following Chemical Formula 2, and a photoinitiator:

wherein R³ is hydrogen, an alkoxycarbonyl group having 1 to 4 carbonatoms, an alkylcarbonyl group having 1 to 4 carbon atoms, or anarylcarbonyl group having 6 to 14 carbon atoms, R⁴ is independently ofeach other hydrogen, halogen, or an alkyl group having 1 to 4 carbonatoms, n is 1 to 4, R⁵ is an alkyl group having 1 to 4 carbon atoms oran aralkyl group having 7 to 15 carbon atoms which may be substituted byan alkyl group having 1 to 4 carbon atoms, R⁶ is an alkyl group having 1to 4 carbon atoms, and X is SbF₆, PF₆, AsF₆, BF₄, CF₃SO₃, N(CF₃SO₂)₂, orN(C₆F₅)₄.

The alkoxy portion of the alkoxycarbonyl group has 1 to 4 carbon atoms,and examples of the alkoxycarbonyl group may include a methoxycarbonylgroup, an ethoxycarbonyl group, a propoxycarbonyl group, and the like.

The alkyl portion of the alkylcarbonyl group has 1 to 4 carbon atoms,and examples of the alkylcarbonyl group may include an acetyl group, apropionyl group, and the like.

The aryl portion of the arylcarbonyl group has 6 to 14 carbon atoms, andexamples of the arylcarbonyl group may include a benzoyl group, a1-naphthylcarbonyl group, a 2-naphthylcarbonyl group, and the like.

Examples of the aralkyl group may include a benzyl group, a2-phenylethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group,and the like.

In exemplary embodiments, the hard coating layer 110 may be formed bycuring the composition for forming a hard coating layer including theepoxy siloxane resin, the thermal initiator including a compoundrepresented by Chemical Formula 2, and the photoinitiator. That is, thehard coating layer 110 may be a cured layer of the composition forforming a hard coating layer.

The epoxy siloxane resin may be for example, a siloxane resin includingan epoxy group. The epoxy group may be any one or more selected from thegroup consisting of a cyclic epoxy group, an aliphatic epoxy group, andan aromatic epoxy group. The siloxane resin may refer to a polymercompound in which a silicon atom and an oxygen atom form a covalentbond.

In some exemplary embodiments, the epoxy siloxane resin may be an epoxygroup-substituted silsesquioxane resin. For example, the epoxy siloxaneresin may be that in which the silicon atom of the silsesquioxane resinis directly substituted by an epoxy group or the substituent on thesilicon atom is substituted by an epoxy group. As a non-limitingexample, the epoxy siloxane resin may be a silsesquioxane resinsubstituted by a 2-(3,4-epoxycyclohexyl)ethyl group.

According to some exemplary embodiments, the epoxy siloxane resin mayhave a weight average molecular weight of 1,000 to 20,000, morepreferably 1,000 to 18,000, and more preferably 2,000 to 15,000. Whenthe weight average molecular weight is within the above range, thecomposition for forming a hard coating layer may have more appropriatedensity. Thus, the flowability, coatability, curing reactivity, and thelike of the composition for forming a hard coating layer may be furtherimproved. In addition, the hardness of the hard coating layer may befurther improved and the flexibility of the hard coating layer isimproved, thereby further suppressing occurrence of curling.

The epoxy siloxane resin according to the present invention may beprepared by alkoxysilane having an epoxy group alone or hydrolysis andcondensation reactions of between alkoxysilane having an epoxy group andanother kind of alkoxysilane, in the presence of water.

According to exemplary embodiments, alkoxysilane having the epoxy groupused in the preparation of the epoxy siloxane resin may be exemplifiedby the following Chemical Formula 3:R⁷ _(n)Si(OR⁸)_(4-n)  [Chemical Formula 3]

wherein R⁷ is a linear or branched alkyl group having 1 to 6 carbonatoms substituted by an epoxycycloalkyl group having 3 to 6 carbon atomsor an oxiranyl group, in which the alkyl group may include an ethergroup, R⁸ is a linear or branched alkyl group having 1 to 7 carbonatoms, and n is an integer of 1 to 3.

The alkoxysilane represented by the above Chemical Formula 3 is notparticularly limited, and examples thereof may include2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,2-(3,4-epoxycyclohexyl)ethyltriethoxysilane,3-glycidoxypropyltrimethoxysilane, and the like. These may be used aloneor in combination of two or more.

In some exemplary embodiments, the epoxy siloxane resin may be includedat 20 to 70 parts by weight, based on 100 parts by weight of the entirecomposition. More preferably, the linear epoxy siloxane compound may beincluded at 20 to 50 parts by weight, based on 100 parts by weight ofthe entire composition. When the above range is satisfied, thecomposition for forming a hard coating layer may secure betterflowability and coating property. In addition, uniform curing ispossible at the time of curing the composition for forming a hardcoating layer to more effectively prevent physical defects such ascracks due to overcuring. In addition, the hard coating layer mayexhibit better hardness.

The thermal initiator may form radicals, cations, or anions by heat andinitiate polymerization of polymerizable compounds. The thermalinitiator may promote the crosslinking reaction of the epoxy siloxaneresin or the crosslinking agent described later when heat is applied tothe composition for forming a hard coating layer.

In exemplary embodiments, the thermal initiator may include a compoundrepresented by Chemical Formula 2. The compound of the followingChemical Formula 2 may be provided, for example, as a cationic thermalinitiator. When the compound of the following Chemical Formula 2 is usedas the thermal initiator, the curing half-life may be shortened.Accordingly, the thermal curing may be performed rapidly even under thelow-temperature conditions, thereby preventing damage and deformationwhich occur in the case of long-term heat treatment under thehigh-temperature conditions.

In some exemplary embodiments, the thermal initiator may be included at0.1 to 20 parts by weight, and more preferably 2 to 20 parts by weight,based on 100 parts by weight of the epoxy siloxane resin. When thecontent of the thermal initiator is within the range, the thermal curingreaction may proceed at a more effective speed. In addition, thecontents of other components of the composition for forming a hardcoating layer may be decreased to effectively prevent the mechanicalproperties (for example, hardness, flexibility, curling property) of thehard coating layer from being deteriorated.

In addition, for example, the thermal initiator may be included at 0.01to 15 parts by weight, based on 100 parts by weight of the entirecomposition. More preferably, the photoinitiator may be included at 0.2to 15 parts by weight, and still more preferably 0.5 to 10 parts byweight, based on 100 parts by weight of the entire composition.

According to some exemplary embodiments, the photoinitiator may includea photo-cationic initiator. The photo-cationic initiator may initiatepolymerization of the epoxy siloxane resin and an epoxy-based monomer.

As the photo-cationic initiator, for example, an onium salt and/or anorganic metal salt may be used, but the photo-cationic initiator is notlimited thereto. For example, a diaryliodonium salt, a triarylsulfoniumsalt, an aryldiazonium salt, an iron-arene complex, and the like may beused. These may be used alone or in combination of two or more.

The content of the photoinitiator is not particularly limited, but forexample, the photoinitiator may be included at 0.1 to 15 parts byweight, and more preferably 1 to 15 parts by weight, based on 100 partsby weight of the epoxy siloxane resin. When the content of thephotoinitiator is within the above range, better curing efficiency ofthe composition for forming a hard coating layer may be maintained, anddeterioration of the physical properties due to residual componentsafter curing may be effectively prevented.

In addition, for example, the photoinitiator may be included at 0.01 to10 parts by weight, based on 100 parts by weight of the entirecomposition. More preferably, the photoinitiator may be included at 0.1to 10 parts by weight, and still more preferably 0.5 to 5 parts byweight, based on 100 parts by weight of the entire composition.

In exemplary embodiments, curing of the composition for forming a hardcoating layer may be performed by photocuring or thermal curing. Inaddition, the curing may be performed by thermal curing afterphotocuring or photocuring after thermal curing, or photocuring andthermal curing may be performed simultaneously. However, in terms of thehardness and curling suppression of the hard coating layer 110, it ismore preferred to perform thermal curing after photocuring.

In some exemplary embodiments, the photocuring using the photoinitiatormay be used in combination with the thermal curing using the thermalinitiator, thereby improving a curing degree, hardness, flexibility, andthe like of the hard coating layer and decreasing curls.

For example, the composition for forming a hard coating layer is appliedto a substrate or the like and is irradiated with ultraviolet rays(photocuring) to at least partially cure the composition, and then heatis further applied (thermal curing) to substantially completely cure thecomposition. Herein, the partial curing may be carried out until thepencil hardness of the cured layer by the ultraviolet curing becomes 1H.

That is, the composition for forming a hard coating layer may besemi-cured or partially cured by the photocuring. The semi-cured orpartially cured composition for forming a hard coating layer may have apencil hardness of about 1H. The semi-cured or partially curedcomposition for forming a hard coating layer may be substantiallycompletely cured by the thermal curing.

For example, when the composition for forming a hard coating layer iscured only by photocuring, a curing time is excessively extended, or inpart, curing may not be completely performed. However, when thephotocuring is followed by the thermal curing, the portion which is notcured by the photocuring may be substantially completely cured by thethermal curing, and the curing time may be also reduced.

In addition, generally, a portion which is appropriately cured isprovided with excessive energy due to an increase in the curing time(for example, an increase in light exposure time), so that overcuringmay occur. When the overcuring proceeds, the cured layer may loseflexibility or mechanical defects such as curls or cracks may occur.However, the photocuring and the thermal curing are used in combination,the composition for forming a hard coating layer may be substantiallycompletely cured within a short time. Thus, the hardness may be improvedand occurrence of curling may be suppressed, while the flexibility ofthe hard coating layer is maintained.

According to some exemplary embodiments, the composition for forming ahard coating layer may further include a crosslinking agent. Thecrosslinking agent may form crosslinks with the epoxy siloxane resin tosolidify the composition for forming a hard coating the cured layer andimprove the hardness of the hard coating layer.

According to some exemplary embodiments, the crosslinking agent mayinclude a compound having an alicyclic epoxy group. For example, thecrosslinking agent may include a compound in which two3,4-epoxycyclohexyl groups are connected. More specifically, forexample, the crosslinking agent may include a compound represented bythe following Chemical Formula 1. The crosslinking agent may havesimilar structure and characteristics to the epoxy siloxane resin. Inthis case, the crosslinking of the epoxy siloxane resin is promoted andthe composition may be maintained at a proper density.

wherein R¹ and R² are independently of each other a linear or branchedalkyl group having 1 to 5 carbon atoms, and X is a direct bond; acarbonyl group; a carbonate group; an ether group; a thioether group; anester group; an amide group; a linear or branched alkylene group,alkylidene group, or alkoxylene group having 1 to 18 carbon atoms; acycloalkylene group or cycloalkylidene group having 1 to 6 carbon atoms;or a connecting group thereof.

In the present specification, a “direct bond” refers to a structurewhich is directly bonded without any functional group. For example, inChemical Formula 1, the direct bond refers to two cyclohexanes directlyconnected to each other. In addition, in the present invention, a“connecting group” refers to two or more substituents described abovebeing connected to each other.

In addition, in Chemical Formula 1, the substitution positions of R¹ andR² are not particularly limited, but when the carbon connected to X isset at position 1, and the carbons connected to an epoxy group are setat positions 3 and 4, it is preferred that R¹ and R² are substituted atposition 6.

The compound described above includes a cyclic epoxy structure in themolecule, and when the epoxy structure is formed in a linear shape as inChemical Formula 1, the viscosity of the composition may be lowered toan appropriate range. When the viscosity is lowered, the coatability ofthe composition is improved and also the reactivity of the epoxy groupis further improved, thereby promoting the curing reaction. In addition,crosslinks with the epoxy siloxane resin is formed to improve thehardness of the hard coating layer.

The content of the crosslinking agent according to the present inventionis not particularly limited, and for example, may be 5 to 150 parts byweight, based on 100 parts by weight of the epoxy siloxane resin. Whenthe content of the crosslinking agent is within the above range, theviscosity of the composition for forming a hard coating layer may bemaintained in a more appropriate range, and coatability and curingreactivity may be further improved.

In addition, the crosslinking agent may be included at 3 to 30 parts byweight, based on 100 parts by weight of the entire composition. Morepreferably, the crosslinking agent may be included at 5 to 20 parts byweight, based on 100 parts by weight of the entire composition.

In some exemplary embodiments, the composition for forming a hardcoating layer may further include a levelling agent.

As the levelling agent, an additive having an excellent levelingproperty and a high surface tension after curing may be used. Forexample, the leveling agent may include at least one selected from thegroup consisting of BYK310, BYK322, BYK325, BYK347, BYK3530, BYK3560,and BYK-LPG21241 from BYK Chemie GmbH; Tego Glide100, Tego Glide406,Tego Glide415, Tego Glide420, Tego Glide450, and Tego Glide B1484 fromEvonik Industries AG; and the like.

The levelling agent may be included at 0.1 to 5 parts by weight, basedon 100 parts by weight of the entire composition. In this case,occurrence of haze in the hard coating layer may be effectivelyprevented.

According to the exemplary embodiments, the composition for forming ahard coating layer may further include a thermal curing agent.

The thermal curing agent may include an amine-based curing agent, animidazole-based curing agent, an acid anhydride-based curing agent, anamide-based thermal curing agents, and the like, and in terms ofdiscoloration prevention and high hardness implementation, it is morepreferred to further use an acid anhydride-based thermal curing agent.These may be used alone or in combination of two or more.

The content of the thermal curing agent is not particularly limited, andfor example, may be 5 to 30 parts by weight, based on 100 parts byweight of the epoxy siloxane resin. When the content of the thermalcuring agent is within the above range, the hardness efficiency of thecomposition for forming a hard coating layer may be further improved toform a hard coating layer having excellent hardness.

In some exemplary embodiments, the composition for forming a hardcoating layer may further include a solvent. The solvent is notparticularly limited and a solvent known in the art may be used.

Non-limiting examples of the solvent may include alcohol-based solvents(such as methanol, ethanol, isopropanol, butanol, methyl cellosolve, andethyl cellosolve), ketone-based solvents (such as methyl ethyl ketone,methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropylketone, and cyclohexanone), hexane-based solvents (such as hexane,heptane, and octane), benzene-based solvents (such as benzene, toluene,and xylene), and the like. These may be used alone or in combination oftwo or more.

The content of the solvent is not particularly limited, and for example,may be 10 to 200 parts by weight, based on 100 parts by weight of theepoxy siloxane resin. When the above range is satisfied, the compositionfor forming a hard coating layer secures an appropriate level ofviscosity, so that workability at the time of forming the hard coatinglayer may be better. In addition, it is easy to control the thickness ofthe hard coating layer, and the solvent drying time is reduced, therebybeing capable of securing a more rapid process speed.

In addition, for example, the solvent may be included at a residualamount excluding the amount of the remaining components in the totalweight of the predetermined entire composition. For example, when thetotal weight of the predetermined entire composition is 100 g and thesum of the weights of the remaining components excluding the solvent is70 g, 30 g of the solvent may be included.

In some exemplary embodiments, the composition for forming a hardcoating layer may further include an inorganic filler. The inorganicfiller may improve the hardness of the hard coating layer.

The inorganic filler is not particularly limited, and examples thereofmay include conductive metal oxides such as silica, alumina, andtitanium oxide; hydroxides such as aluminum hydroxide, magnesiumhydroxide, and potassium hydroxide; metal particles such as gold,silver, copper, nickel, and an alloy thereof; conductive particles suchas carbon, carbon nanotubes, and fullerene; glass; ceramic; and thelike. Preferably, silica may be used in terms of compatibility withother components of the composition for forming a hard coating layer.These may be used alone or in combination of two or more.

In some exemplary embodiments, the composition for forming a hardcoating layer may further include a lubricant. The lubricant may improvewinding efficiency, blocking resistance, wear resistance, scratchresistance, and the like.

The kind of the lubricants is not particularly limited, and for example,waxes such as polyethylene wax, paraffin wax, synthetic wax, or montanwax; synthetic resins such as a silicone-based resin or a fluorine-basedresin; and the like may be used. These may be used alone or incombination of two or more.

In addition, the composition for forming a hard coating layer mayfurther include additives such as, for example, an antioxidant, a UVabsorber, a photostabilizer, a thermal polymerization inhibitor, asurfactant, a lubricant, and an antifouling agent.

The thickness of the hard coating layer 110 is not particularly limited,and for example, may be 5 to 100 μm, and more preferably 5 to 50 μm.When the thickness of the hard coating layer 110 is within the range,the hard coating layer maintains flexibility while having excellenthardness, so that curls may not substantially occur.

In some exemplary embodiments, the antireflection hard coating film 10may have a curl amount of 5 mm or less, in which the curl amount ismeasured at each vertex of a square sample cut so that the length ofeach side is 10 cm and each side is inclined at an angle of 45° to an MDdirection of the film.

The curl may refer to a vertical height from the lowest position (forexample, a center) to the vertex of the film, for each vertex of thesample of the antireflection hard coating film cut into a square whichis inclined at an angle of 45° to the MD direction and has each side of10 cm in length. In the present specification, the MD direction is amachine direction, and refers to a direction in which the film movesalong an automated machine when the film is drawn or laminated by anautomation process. As the curl is measured for the sample inclined atthe angle of 45° to the MD direction, the curls at each vertex meanscurls to the MD direction and a direction perpendicular to the MDdirection, thereby distinguishing the curls.

In some exemplary embodiments, the hard coating layer 110 may have arefractive index of 1.48 to 1.55.

According to some exemplary embodiments, the hard coating layer 110 maybe formed on one surface of the substrate 100, or the hard coating layer110 may be formed on both surfaces of the substrate 100.

The conductive layer 120 is disposed on a surface opposite to the sidewhere the substrate 100 of the hard coating layer 110 is positioned.

The conductive layer 120 may impart an antistatic property to theantireflection hard coating film 10.

The conductive layer 120 may adopt and include any material withoutlimitation, as long as the material may impart an antistatic property tothe antireflection hard coating film 10.

However, the material included in the conductive layer 120 may be amaterial having high light transmittance and refractive index. In thiscase, the antireflection property may be implemented by a difference ina refractive index between the conductive layer 120 and the lowrefractive index layer 130.

In some exemplary embodiments, the conductive layer 120 may include aconductive metal oxide or a conductive metal nitride.

Hereinafter, for convenience of description, description will be givenbased on the conductive metal oxide. The following description for theconductive metal oxide may correspond to the conductive metal nitride.

The conductive metal oxide may mean that it includes a conductivemetalloid oxide.

The conductive metal oxide may mean that it includes a metal oxidehaving conductivity in itself. Of course, those doped with impuritiesmay be included. The impurities may be, for example, a non-metalelement, a metalloid element, a metal element, and the like.

In addition, the conductive metal oxide may mean that a metal oxidehaving conductivity by doping with impurities is included. Theimpurities may be, for example, a non-metal element, a metalloidelement, a metal element, and the like.

In some exemplary embodiments, the conductive metal oxide or theconductive metal nitride may include any one or more selected from thegroup consisting of an aluminum (Al) oxide doped with any one or moreselected from the group consisting of phosphorus (P), indium (In),antimony (Sb), and the like; a titanium (Ti) oxide doped with any one ormore selected from the group consisting of phosphorus, indium, antimony,and the like; an antimony oxide doped with any one or more selected fromthe group consisting of phosphorus, indium, and the like; and the like.In this case, the antireflection hard coating film may secure excellentantistatic performance and antireflection performance.

For example, a titanium oxide doped with phosphorus, indium, or antimonymay have electroconductivity. In addition, phosphorus, indium, orantimony may stabilize the titanium oxide and reinforce strength of thetitanium oxide. In particular, the titanium oxide doped with phosphorus,indium, or antimony may have high transparency and refractive index.Thus, the antireflection hard coating film may secure particularlyexcellent antistatic performance and antireflection performance.

In some exemplary embodiments, the conductive layer 120 may be formed ofa single material of the conductive metal oxide or the conductive metalnitride.

According to some exemplary embodiments, the conductive layer 120 may beformed by sputtering the conductive metal oxide or the conductive metalnitride. In addition, the conductive layer 120 may be formed bysputtering a metal element while supplying oxygen. In this case, theconductive layer 120 may have a uniform and small thickness, and havebetter hardness and light transmission, as compared with the film formedby wet-drying the solvent. In addition, more improved antireflection andantistatic effects may be implemented.

In some exemplary embodiments, the refractive index of the conductivelayer 120 may be higher than the refractive indexes of the hard coatinglayer 110 and the low refractive index layer 130.

In some exemplary embodiments, the conductive layer 120 may have arefractive index of 1.6 to 2.6.

In some exemplary embodiments, the antireflection hard coating film mayhave a surface resistance of 10⁷Ω/□(Ω/sq) to 10¹³Ω/□, and morepreferably 10⁸Ω/□ to 10¹¹Ω/□.

The low refractive index layer 130 is disposed on a surface opposite tothe side where the hard coating layer 110 of the conductive layer 120 ispositioned. The refractive index of the low refractive index layer 130may be lower than the refractive index of the conductive layer 120.

In some exemplary embodiments, the low refractive index layer 130 mayinclude an inorganic oxide. As the inorganic oxide, a material having ahigh light transmittance and a refractive index lower than therefractive index of the conductive metal oxide or the conductive metalnitride of the conductive layer 120, may be used.

The inorganic oxide may be an oxide of a metalloid element.

For example, the inorganic oxide may include silicon dioxide (SiO₂) andthe like. The silicon dioxide has a refractive index lower than therefractive index of the conductive metal oxide or the conductive metalnitride of the conductive layer 120 and a sufficient light transmission,and thus, may be appropriate for an antireflective coating.

In some exemplary embodiments, the low refractive index layer 130 may beformed of a single material of the inorganic oxide.

According to some exemplary embodiments, the low refractive index layer130 may be formed by sputtering the inorganic oxide. In this case, thelow refractive index layer 130 may have a uniform and small thickness,and have better hardness, as compared with the film formed by wet-dryingthe solvent. In addition, a purity may be high without impurities suchas solvent residues, and light transmission may be better. In addition,a more improved antireflection effect may be implemented.

In some exemplary embodiments, the low refractive index layer 130 mayhave a refractive index of 1.35 to 1.45.

FIG. 2 is schematic drawings illustrating an antireflection hard coatingfilm according to the exemplary embodiments of the present invention.

Referring to FIG. 2 , in some exemplary embodiments, the conductivelayer 120 and the low refractive index layer 130 may be defined as anantireflection laminate 125, and the antireflection laminate 125 may belaminated several times repeatedly.

In the antireflection laminate 125, the antireflection effect of lightincident on the low refractive index layer 130 may be implemented by adifference in a refractive index between the conductive layer 120 andthe low refractive index layer 130.

In exemplary embodiments, the antireflection laminate 125 may belaminated two to six times repeatedly. In this case, an excellentantireflection effect may be implemented. In addition, a decrease in alight transmittance and a decrease in visibility to a lower surface ofthe antireflection hard coating film may be effectively prevented.

FIG. 3 is schematic drawings illustrating an antireflection hard coatingfilm according to the exemplary embodiments of the present invention.

Referring to FIG. 3 , the antireflection hard coating film according tothe exemplary embodiments of the present invention may further includean antifouling layer 140 disposed on the low refractive index layer 130.

In some exemplary embodiments, the antifouling layer 140 may include ametal fluoride. In this case, the antifouling layer 140 may secure waterrepellent, water-proof, and oil-proof performances.

In some exemplary embodiments, the metal fluoride may include magnesium(Mg), barium (Ba), and the like. In this case, the antifouling layer 140may secure particularly excellent light transmission and waterrepellency.

In some exemplary embodiments, the antifouling layer 140 may be formedof a single material of the metal fluoride.

In some exemplary embodiments, the antifouling layer 140 may be formedby sputtering the metal fluoride. In this case, the antifouling layer140 may have a uniform and small thickness, as compared with the filmformed by wet-drying the solvent. In addition, a purity may be highwithout impurities such as solvent residues, and light transmission maybe better. In addition, better scratch resistance and antifoulingperformance may be exhibited.

In some exemplary embodiments, the antifouling layer 140 may have arefractive index of 1.30 to 1.60.

FIG. 4 is schematic flow charts representing a preparation method of ahard coating film according to the exemplary embodiments of the presentinvention.

According to exemplary embodiments, a composition for forming a hardcoating layer may be applied on a substrate (for example, S10).

As the composition for forming a hard coating layer, the composition forforming a hard coating layer according to the above-described exemplaryembodiments of the present invention may be used.

The application (for example, S10) may be carried out by a die coater,an air knife, a reverse roll, spray, a blade, casting, gravure, spincoating, and the like.

According to some exemplary embodiments, the composition for forming ahard coating layer may be cured to form a hard coating layer (forexample, S20).

In exemplary embodiments, curing of the composition for forming a hardcoating layer may be performed by photocuring, or also performed bythermal curing. In addition, the curing may be performed by thermalcuring after photocuring or photocuring after thermal curing, orphotocuring and thermal curing may be performed simultaneously. However,in terms of the hardness and curling suppression of the hard coatinglayer, it is more preferred to perform thermal curing after photocuring.The photocuring may be performed by ultraviolet irradiation.

The composition for forming a hard coating layer may be at leastpartially photocured by the ultraviolet irradiation.

In exemplary embodiments, the ultraviolet irradiation may be carried outso that a curing degree of the composition for forming a hard coatinglayer is about 20 to 80%. When the curing degree is within the range,the hard coating layer is primarily cured to secure hardness, andsimultaneously prevents an overcuring phenomenon due to an extendedlight exposure time.

For example, the ultraviolet irradiation may be carried out so that apencil hardness of the cured hard coating layer is 1H or less. That isto say, the ultraviolet irradiation is finished before the pencilhardness of the hard coating layer becomes about 1H, and the thermalcuring may be carried out.

For example, heat is applied to the hard coating layer composition whichhas been primarily partially cured by ultraviolet irradiation tosubstantially completely cure the composition. When the photocuring andthe thermal curing having different curing mechanisms are used incombination, the curing time is shortened as compared with the case inwhich the photocuring or the thermal curing is carried out alone forcuring, thereby suppressing the overcuring phenomenon. In addition, thecrosslinking reaction is effectively derived to allow the crosslinks tobe uniformly formed. In addition, the hard coating layer may maintainflexibility while having improved hardness, and curls of theantireflection hard coating film may be significantly decreased.

In some exemplary embodiments, the thermal curing may be carried out ata temperature of 100 to 200° C. for 5 to 20 minutes. More preferably,the thermal curing may be carried out at a temperature of 120 to 180° C.Within the temperature range, the thermal curing may proceed at a moreeffective speed. In addition, crack occurrence due to thermaldecomposition or a side reaction of each component in the compositionfor forming a hard coating layer or overcuring of the hard coating layermay be effectively prevented.

According to exemplary embodiments, pretreatment may be carried out byheating the composition for forming a hard coating layer beforeultraviolet irradiation. In the pretreatment process, a solvent havinghigh volatility may be evaporated before ultraviolet irradiation. Thus,occurrence of air bubbles or non-uniform curing during ultravioletirradiation may be prevented.

The pretreatment may be carried out at lower temperature than thethermal curing temperature, and for example, carried out at 40 to 80° C.Within the temperature range, the solvent may be effectively evaporatedwhile the initiation reaction of the thermal initiator does not occur.

According to exemplary embodiments, the conductive layer is formed onthe hard coating layer (for example, S30).

In some exemplary embodiments, the formation of the conductive layer maybe performed by sputtering a conductive metal oxide or conductive metalnitride or sputtering a metal element while supplying oxygen.

In some exemplary embodiments, the conductive metal oxide or theconductive metal nitride may include any one or more selected from thegroup consisting of an aluminum (Al) oxide doped with any one or moreselected from the group consisting of phosphorus (P), indium (In),antimony (Sb), and the like; a titanium (Ti) oxide doped with any one ormore selected from the group consisting of phosphorus, indium, antimony,and the like; an antimony oxide doped with any one or more selected fromthe group consisting of phosphorus, indium, and the like; and the like.

In some exemplary embodiments, the conductive layer may be formed ofonly the conductive metal oxide or the conductive metal nitride.

According to exemplary embodiments, the low refractive index layer isformed on the conductive layer (for example, S40).

In some exemplary embodiments, the formation of the low refractive indexlayer may be performed by sputtering an inorganic oxide.

In some exemplary embodiments, the inorganic oxide may include silicondioxide (SiO₂) and the like.

In some exemplary embodiments, the low refractive index layer may beformed of only the inorganic oxide.

Formation of the conductive layer and formation of the low refractiveindex layer may be performed several times repeatedly, and the formationis performed to be completed by the formation of the low refractiveindex layer.

FIG. 5 is schematic flow chart representing a preparation method of anantireflection hard coating film according to the exemplary embodimentsof the present invention.

Hereinafter, referring to FIG. 5 , the preparation method of theantireflection hard coating film according to the exemplary embodimentsof the present invention will be described. However, detaileddescription may be omitted for the same process as the process describedabove referring to FIG. 4 .

According to exemplary embodiments, an antifouling layer may be formedon the low refractive index layer (for example, S50). In this case, anantireflection hard coating film having improved scratch resistance,water contact angle, and antifouling performance may be prepared.

In some exemplary embodiments, formation of the antifouling layer may beperformed by sputtering a metal fluoride.

In some exemplary embodiments, the metal fluoride may include magnesium(Mg), barium (Ba), and the like.

In some exemplary embodiments, the antireflection hard coating film 10has a high surface hardness and excellent flexibility, and is thinnerand has better impact resistance than a tempered glass, and thus, may bepreferably used as a window substrate of the outermost surface of thedisplay panel.

According to some exemplary embodiments, an image display including theantireflection hard coating film 10 may be provided.

The antireflection hard coating film 10 may be used as a windowsubstrate of the outermost surface of the image display. The imagedisplay may be various image displays such as a common liquid crystaldisplay, an electroluminescence display, a plasma display, and a fieldemission display.

Hereinafter, preferred examples will be provided in order to assist inthe understanding of the present invention. However, it will be obviousto those skilled in the art that these examples only illustrate thepresent invention and do not limit the appended claims, and variousmodifications and alterations of the examples may be made within therange of the scope and spirit of the present invention, and thesemodifications and alterations will fall within the appended claims.

Preparation Example 1

2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane (ECTMS, TCI Co., Ltd.) andwater (H₂O, Sigma-Aldrich Corporation) were mixed at a ratio of 24.64g:2.70 g (0.1 mol:0.15 mol) and placed in a 250 mL 2-neck flask.Thereafter, 0.1 mL of a tetramethylammonium hydroxide catalyst(Sigma-Aldrich) and 100 mL of tetrahydrofuran (Sigma-Aldrich) were addedto the mixture and stirred at 25° C. for 36 hours. Then, layerseparation was performed and a product layer was extracted withmethylene chloride (Sigma-Aldrich), and moisture was removed from theextract with magnesium sulfate (Sigma-Aldrich) and the solvent was driedunder vacuum to obtain an epoxy siloxane resin. As a result of measuringthe epoxy siloxane resin using gel permeation chromatography (GPC), theweight average molecular weight was 2500.

Example 1

30 parts by weight of the epoxy siloxane resin prepared in PreparationExample 1, 15 parts by weight of (3′,4′-epoxycyclohexyl)methyl3,4-epoxycyclohexanecarboxylate (Daicel Corporation, Celloxide 2021P), 1part by weight of 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate(SANSHIN CHEMICAL INDUSTRY CO., LTD., SI-60), 1 part by weight of(4-methylphenyl) [4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate,0.3 parts by weight of a silicone polymer (BYK Additives & Instruments,BYK3560, a levelling agent), and 52.7 parts by weight of methyl ethylketone (Sigma-Aldrich) were mixed to prepare a composition for forming ahard coating layer.

The composition for forming a hard coating layer was applied on acolorless polyimide (cPI) film having a thickness of 80 μm by a Meyerbar method, and was allowed to stand at a temperature of 60° C. for 5minutes.

The applied composition was irradiated with UV at 1 J/cm² using ahigh-pressure metal lamp and then was cured at a temperature of 120° C.for 15 minutes to form a hard coating layer having a thickness of 10 μm,a refractive index of 1.51, and a water contact angle of 79°.

Titanium dioxide (TiO₂) doped with indium (In) was sputtered on theupper surface of the hard coating layer to form a conductive layerhaving a refractive index of 2.0.

SiO₂ was sputtered on the upper surface of the conductive layer to forma low refractive index layer having a refractive index of 1.45, therebypreparing an antireflection hard coating film.

Example 2

An antireflection hard coating film was prepared in the same manner asin Example 1, except that the conductive layer was replaced with theconductive layer having a refractive index of 2.5, formed by sputteringtitanium dioxide doped with antimony (Sb).

Example 3

An antireflection hard coating film was prepared by forming theconductive layer and the low refractive index layer once more repeatedlyon the low refractive index layer in Example 1.

Example 4

An antireflection hard coating film was prepared by forming theconductive layer and the low refractive index layer two times morerepeatedly on the low refractive index layer in Example 1.

Example 5

In Example 1, the conductive layer and the low refractive index layerwere formed two times more repeatedly on the low refractive index layer.

Thereafter, MgF₂ was sputtered on the upper surface of the outermostlayer to form an antifouling layer having a refractive index of 1.38,thereby preparing an antireflection hard coating film.

Comparative Example 1

An antireflection hard coating film was prepared in the same manner asin Example 1, except that the conductive layer was replaced with thehigh refractive index layer having a refractive index of 2.0, formed bysputtering hafnium dioxide (HfO₂).

Comparative Example 2

20 parts by weight of pentaerythritol tetraacrylate, 20 parts by weightof o-phenylphenoxyethyl acrylate, 1 part by weight of1-hydroxylcyclohexyl phenyl ketone, 0.3 parts by weight of a siliconepolymer (BYK Additives & Instruments, BYK300, a levelling agent), and58.7 parts by weight of methyl ethyl ketone (Sigma-Aldrich) were mixedto prepare a hard coating composition of the Comparative Example.

The hard coating composition was applied on a cPI film having athickness of 80 μm by a Meyer bar method, and was allowed to stand at atemperature of 60° C. for 5 minutes.

The applied composition was irradiated with UV at 1 J/cm² using a highpressure metal lamp to form a hard coating layer having a thickness of10 μm and a refractive index of 1.54.

Titanium dioxide doped with indium was sputtered on the upper surface ofthe hard coating layer to form a conductive layer having a refractiveindex of 2.0.

SiO₂ was sputtered on the upper surface of the conductive layer to forma low refractive index layer having a refractive index of 1.45, therebypreparing an antireflection hard coating film.

Comparative Example 3

An antireflection hard coating film was prepared in the same manner asin Example 2, except that the conductive layer was replaced with thehigh refractive index layer having a refractive index of 2.0, formed bysputtering hafnium dioxide (HfO₂).

Experimental Example

The pencil hardness, the curl amount, the reflectance, thetransmittance, and the antistatic property of the antireflection hardcoating films of the Examples and the Comparative Examples wereevaluated.

In addition, interlayer bonding force between the hard coating layer andthe layers formed on the hard coating layer of the Examples and theComparative Examples were evaluated.

The water contact angle of the hard coating layers of the Examples andthe Comparative Examples were measured using a contact angle measuringinstrument (MSA, KRUSS GmbH), before forming other layers.

1. Measurement of Pencil Hardness

A pencil hardness on the outermost surface of the antireflection hardcoating film was measured using pencils by hardness (Mistubishi PencilCo., Ltd.) under a load of 1 kg using a pencil hardness tester (KipaeE&T Co. Ltd.) in accordance with ASTM D3363.

2. Measurement of Curl Amount

The antireflection hard coating film was cut into a square of 10 cm×10cm inclined at an angle of 45° to an MD direction and allowed to standat 25° C., 50% for 12 hours under constant temperature and humidityconditions, and then the curling degree of each vertex was measuredusing a ruler.

3. Measurement of Reflectance

A spectrophotometer UV3600 (Shimadzu Corporation) was equipped with anadaptor MPC603, a specular reflectance to an output angle of 5° at anincident angle of 5° in a wavelength range of 380 to 780 nm wasmeasured, and an average reflectance of 400 to 800 nm was calculated.

4. Measurement of Transmittance

The total transmittance of the antireflection hard coating film wasmeasured using a spectrophotometer (COH-400, Nippon Denshoku Industries,Co., Ltd).

5. Measurement of Antistatic Property

On three points on the surface of the outermost layer of theantireflection hard coating film, the surface resistance was measured at500 V for 10 seconds, using a high resistivity meter(MCP-HT800/MITSUBISHI CHEMICAL ANALYTECH) and a probe (URS, UR 100).

6. Evaluation of Interlayer Bonding Force

The antireflection hard coating film was cut into a size of 7 cm×12 cmand fixed to a jig of a wear resistance tester (manufactured by KipaeE&T Co. Ltd.), and steel wool (#0000, Liberon Limited) was provided inand fixed to a tip having a diameter of 22 mm. A moving distance of 100mm, a moving speed of 60 mm/min, and a load of 1.0 kg were set, and thesurface of the outermost layer of the antireflection hard coating filmwas rubbed with steel wool 10 times reciprocatively. Thereafter, it wasconfirmed whether exfoliation between the hard coating layer and thelayers formed on the hard coating layer occurred (bonding force).

TABLE 1 Water contact angle of hard Pencil Curl coating ReflectanceTransmittance Surface Bonding Classification hardness amount layer (%)(%) roughness force Example 8H 0.5 mm 79 0.5 94.3 10⁹ Ω/cm² Not 1exfoliated Example 8H 0.5 mm 78 0.4 94.6 10⁹ Ω/cm² Not 2 exfoliatedExample 8H 0.5 mm 80 0.3 94.7 10⁹ Ω/cm² Not 3 exfoliated Example 8H 0.5mm 80 0.2 94.8 10⁹ Ω/cm² Not 4 exfoliated Example 8H 0.5 mm 79 0.3 94.810⁹ Ω/cm² Not 5 exfoliated Comparative 8H   3 mm 79 0.8 93.2Unmeasurable Not Example exfoliated 1 Comparative 3H  50 mm 95 1.0 93.010⁹ Ω/cm² Exfoliated Example 2 Comparative 3H  50 mm 96 1.0 92.7Unmeasurable Exfoliated Example 3

Referring to Table 1, it was confirmed that the antireflection hardcoating films according to the Examples of the present invention had asignificantly better antistatic property than the antireflection hardcoating films of the Comparative Examples.

In addition, it was confirmed that the Examples had significantly betterhardness, anti-curling property, reflectance, and transmittance than theComparative Examples.

According to the exemplary embodiments of the present invention, a hardcoating layer having a water contact angle of 90° or less, a conductivelayer, and a low refractive index layer are laminated. Thus, anantireflection hard coating film having improved interlayer bondingforce between the hard coating layer and the conductive layer may beprovided. In addition, the antireflection hard coating film may secureexcellent hardness, anti-curling property, antistatic property, andantireflection property.

In addition, the hard coating layer includes an epoxy siloxane resin, aspecific thermal initiator, and a photoinitiator to further improve thehardness and the anti-curling property of the antireflection hardcoating film.

According to some exemplary embodiments, the composition for forming ahard coating layer may be sequentially photocured and thermally cured toform the hard coating layer, thereby further improving the hardness andthe anti-curling property of the antireflection hard coating film.

In addition, the conductive layer may be formed by sputtering theconductive metal oxide or the conductive metal nitride, thereby furtherimproving the hardness, the anti-curling property, and theantireflection property and securing the antistatic effect.

In addition, the low refractive index layer may be formed by sputteringan inorganic oxide, thereby improving the hardness, the anti-curlingproperty, and antireflection property of the hard coating film.

The antireflection hard coating film according to some exemplaryembodiments may further include an antifouling layer including a metalfluoride to exhibit excellent scratch resistance and antifoulingperformance.

What is claimed is:
 1. An antireflection hard coating film comprising: asubstrate; a hard coating layer having a water contact angle of 90° orless, disposed on the substrate; a conductive layer disposed on the hardcoating layer; and a low refractive index layer disposed on theconductive layer, wherein the water contact angle of the hard coatinglayer is measured using a contact angle measuring instrument, whereinthe antireflection hard coating film has a curl amount of 5 mm or lessmeasured by cutting a 10 cm×10 cm square sample from the film inclinedat an angle of 45° to a MD direction of the film and exposing the squaresample to 25° C. and 50% humidity for 12 hours, wherein the curl amountis a maximum vertical height measured from a lowest position of thesquare sample to each vertex of the square sample, wherein the hardcoating layer is a cured layer of a composition for forming a hardcoating layer comprising an epoxy siloxane resin, a crosslinking agent,a thermal initiator including a compound represented by the followingChemical Formula 2, and a photoinitiator:

wherein R³ is hydrogen, an alkoxycarbonyl group having 1 to 4 carbonatoms, an alkylcarbonyl group having 1 to 4 carbon atoms, or anarylcarbonyl group having 6 to 14 carbon atoms, R⁴ is independently ofeach other hydrogen, halogen, or an alkyl group having 1 to 4 carbonatoms, n is 1 to 4, R⁵ is an alkyl group having 1 to 4 carbon atoms oran aralkyl group having 7 to 15 carbon atoms which may be substituted byan alkyl group having 1 to 4 carbon atoms, R⁶ is an alkyl group having 1to 4 carbon atoms, and X is SbF₆, PF₆, AsF₆, BF₄, CF₃SO₃, N(CF₃SO₂)₂, orN(C₆F₅)₄, wherein the epoxy siloxane resin is prepared by hydrolysis anda condensation reaction of an alkoxysilane having an epoxy grouprepresented by the following Chemical Formula 3:R⁷Si(OR⁸)₃  [Chemical Formula 3], wherein R⁷ is a linear or branchedalkyl group having 1 to 6 carbon atoms substituted by an epoxycycloalkylgroup having 3 to 6 carbon atoms or substituted by an oxiranyl group, inwhich the alkyl group may include an ether group, R⁸ is a linear orbranched alkyl group having 1 to 7 carbon atoms, wherein the conductivelayer includes any one or more selected from the group consisting of analuminum (Al) oxide doped with any one or more selected from the groupconsisting of phosphorus (P), indium (In), and antimony (Sb); a titanium(Ti) oxide doped with any one or more selected from the group consistingof phosphorus, indium, and antimony; and an antimony oxide doped withany one or more selected from the group consisting of phosphorus andindium, wherein the crosslinking agent includes a compound representedby the following Chemical Formula 1:

wherein R¹ and R² are independently of each other a linear or branchedalkyl group having 1 to 5 carbon atoms, and X is a direct bond; acarbonyl group; a carbonate group; an ether group; a thio ether group;an ester group; an amide group; a linear or branched alkylene group,alkylidene group, or alkoxylene group having 1 to 18 carbon atoms; or acycloalkylene group or cycloalkylidene group having 1 to 6 carbon atoms,wherein the substrate has a thickness of 10 to 250 μm and comprises atleast one selected from the group consisting of a polyester-based resina cellulose-based resin, a polycarbonate-based resin, an acrylic resin,a styrene-based resin, a polyolefin-based resin, a polyimide-basedresin, a polyaramide-based resin, a polyamideimide-based resin, apolyethersulfone-based resin and a sulfone-based resin, wherein thecured hard coating layer has a thickness of 5 to 100 μm, and wherein theepoxy siloxane resin is included at 20-70 parts by weight, the thermalinitiator is included at 0.01-15 parts by weight, the photoinitiator isincluded at 0.01-10 parts by weight, and the crosslinker is included at3-30 parts by weight, based on 100 parts by weight of the entirecomposition.
 2. The antireflection hard coating film of claim 1, whereinthe cured hard coating layer is formed by photocuring and then thermallycuring the composition for forming a hard coating layer.
 3. Theantireflection hard coating film of claim 1, wherein the low refractiveindex layer includes an inorganic oxide.
 4. The antireflection hardcoating film of claim 3, wherein the inorganic oxide includes silicondioxide (SiO₂).
 5. The antireflection hard coating film of claim 1,wherein the antireflection hard coating film has a surface resistance of10⁷ Ω/cm² to 10¹³ Ω/cm².
 6. The antireflection hard coating film ofclaim 1, wherein the conductive layer has a refractive index of 1.6 to2.6, and the low refractive index layer has a refractive index of 1.35to 1.45.
 7. The antireflection hard coating film of claim 1, wherein thehard coating layer has a refractive index of 1.48 to 1.55.
 8. Theantireflection hard coating film of claim 1, wherein when the conductivelayer and the low refractive index layer are defined as anantireflection laminate, the antireflection laminate is laminated two tosix times repeatedly.
 9. The antireflection hard coating film of claim1, further comprising: an antifouling layer including a metal fluoride,disposed on the low refractive index layer.
 10. The antireflection hardcoating film of claim 9, wherein the metal fluoride includes magnesium(Mg) or barium (Ba).